WASHINGTON â Ever since the Army lost its warplanes to a newly independent Air Force after World War II, soldiers have depended on the sister service for help from the sky, from bombing and strafing to transport and surveillance.

But the wars in Iraq and Afghanistan have frayed the relationship, with Army officers making increasingly vocal complaints that the Air Force is not pulling its weight.

.....

But now in Iraq, the Army has quietly decided to try going it alone for the important surveillance mission, organizing an all-Army surveillance unit that represents a new move by the service toward self-sufficiency, and away from joint operations.

Senior aides to Defense Secretary Robert M. Gates say that he has shown keen interest in the Army initiative â much to the frustration of embattled Air Force leaders â as a potential way to improve battlefield surveillance.

The work of the new aviation battalion was initially kept secret, but Army officials involved in its planning say it has been exceptionally active, using remotely piloted surveillance aircraft to call in Apache helicopter strikes with missiles and heavy machine gun fire that have killed more than 3,000 adversaries in the last year and led to the capture of almost 150 insurgent leaders.

The Army aviation task force became fully operational last July with headquarters at Camp Speicher, in the north-central city of Tikrit, and focuses its efforts on insurgents planting roadside bombs. But it also has located and attacked insurgents in battles with American and Iraqi troops, and has supported missions of the top-secret Special Operations units assigned to capture or kill the most high-value targets in Iraq.

The battalion is called Task Force Odin â the name is that of the chief god of Norse mythology, but it also is an acronym for âobserve, detect, identify and neutralize.â The task force of about 300 people and 25 aircraft is a Rube Goldberg collection of surveillance and communications and attack systems, a mash-up of manned and remotely piloted vehicles, commercial aircraft with high-tech infrared sensors strapped to the fuselage, along with attack helicopters and infantry.

The Army cobbled together small civilian aircraft, including the Beech C-12, and placed advanced reconnaissance sensors on board. Also assigned to the task force are small, medium and larger remotely piloted Army surveillance vehicles, including the Warrior and Shadow, with infrared cameras for night operations and full-motion video cameras.

All are linked by radio to Apache attack helicopters, with Hellfire missiles and 30-millimeter guns, and to infantry units in armored vehicles.

......

In contrast to Predators, which are assigned by the top headquarters for missions all across Iraq, Task Force Odin is on call for commanders at the level of brigade and below, an effort by the Army to be responsive to the needs of smaller combat units in direct contact with adversaries â and a clear sign of rivaling concepts with the Air Force.

.....

Geoff Morrell, the Pentagon press secretary, said Mr. Gates âwants to make sure that we are looking at not just top-down solutions, but ground-up solutions. We need to pay attention to anything that works.â

.....

Army and Marine Corps officers in Afghanistan have complained that Air Force pilots flying attack missions in support of ground operations do not come in as low as their Navy and Marine counterparts.

.....

The Army is asking for money to create a similar unit in Afghanistan within the next six months.